The invention, in some embodiments, relates to the field of agriculture, and more particularly, but not exclusively, to methods and devices suitable for incubating eggs for poultry farming.
Poultry farming, raising birds for meat and eggs, is an important industry. Bird species raised in poultry farming include chicken, turkey, duck, goose, quail, pheasant, pigeon (including doves), partridges and to a lesser extent ostrich. Worldwide, more than 50 billion chickens are raised annually for meat and eggs.
A first step in poultry farming involves producing chicks by incubating fertilized eggs in an incubator until the eggs hatch. It is accepted that up to 90% of eggs placed in an industrial incubator are actually fertile.
It is accepted in the art that the highest hatch rate (the proportion of fertile eggs that hatch and give viable chicks) in industrial incubators is achieved when the eggs are maintained at a stable and constant temperature. For instance, it is accepted that in an industrial incubator, variations of more than 0.1° C. from the optimal 37.5° C. will reduce hatch rates. Accordingly, industrial incubators are maintained at 37.5°±0.1 C during the incubation process. Furthermore, it is known in the art that to prevent embryos from adhering to the internal egg walls and developing defects, the eggs must be moved during incubation. In industrial incubators, the eggs are periodically tilted through +45″.
During optimal incubation, eggs lose between 13% and 17% weight, primarily due to water loss by evaporation through the eggshell. The rate of weight loss is dependent on factors such as incubation temperature, relative humidity and eggshell thickness that depend, inter alia, on the species and diet of the laying hen. During incubation using industrial incubators, it is known to weigh a sample of eggs every few days and compare the average weight loss of the sampled eggs to a known graph of weight loss as a function of incubation time. Deviations are corrected by changing the relative humidity of the atmosphere in the incubator, i.e., increasing the relative humidity if the average weight is too low indicating that the rate of water evaporation from the eggs is too high and decreasing the relative humidity if the average weight is too high indicating that the rate of water evaporation from the eggs is too low.
It has been found that under ideal conditions of temperature, movement and adjusting humidity based on weight-loss monitoring, less than 90% of the up to 90% fertile eggs hatch to yield a viable chick.
The present Inventor has previously developed a small-scale incubator (having a capacity of up to about 50 parrot eggs) commercially sold as the Inca Incubator. Although originally designed for incubating parrot eggs, the incubator has been used with great success for incubating eggs of all species, for example, falcons and hummingbirds.
In the Inca incubator, the eggs rest on the floor of the incubator between movable rods. During incubation, the atmosphere in the incubator is maintained at 37.5±1° C., while the temperature of the floor on which the eggs rest is lower, typically 35.0-35.5° C. Every 60 to 90 minutes, the rods are moved, rolling the eggs to achieve rotation around the egg axis of between about 160° and about 220°. Like in industrial incubators, the weight loss of the incubating eggs is monitored and humidity is adjusted to keep the rate of weight loss within the accepted values.
The Inca incubators have been found to have a close to 100% hatch rate of fertilized eggs. Without wishing to be held to any one theory, it is believed that a reason for such a high hatch rate is a result of emulating natural incubation by brooding birds: the egg resting on a surface cooler than the incubator atmosphere leads to a temperature gradient across the egg throughout the incubation period emulating natural incubation where the portion of an egg resting at the bottom of a nest is cooler than the portion in contact with the brooding adult's body leading to a temperature gradient across the egg while the intermittent rolling of around 180° mimics the intermittent rotation of the eggs by the adult bird.
Methods and devices for incubating avian eggs, especially on an industrial scale, are sought after.